Deep red beryl crystals are found only in North America, where they are associated with light gray Tertiary volcanic rocks, specifically kaolinized sections in topaz-bearing rhyolites. The largest deposit is located in Utah, extending south from the Thomas Range into the Wah Wah Mountains. The "Ruby Violet Mine" in Beaver County, in the southern part of the Wah Wah Mountains (Ream 1979), is considered the best locality. It yielded by far the largest and finest red beryl crystals; its violet-red, partially clear prisms can, in exceptional cases, reach lengths of 2–5 cm and thicknesses of 1–2 cm. Prospector Lamar Hodges discovered the deposit in 1958 and worked it until 1976 ("Violet Claims 1–8"); then, Rex and Ed Harris, as family businesses, took over the mining operations. By 1994, three open-pit mines, reaching depths of up to 20 meters, had been established (the "Ruby Violet Mine"). From 1994 to 1996, Kennecott Exploration Co. explored the deposit using trenches, boreholes, and adits, searching for clear, cut-quality red beryl; however, only gem-quality grades of 0.2–1 gram per ton of rock were detected. From 1997 to 2001, Gemstone Mining Inc. continued exploration and mining operations (the "Red Emerald Mine"). This venture failed in August 2001, and all open-pit mines were backfilled and the area reclaimed. The land is still owned by the Harris Family, but since then, red beryl crystals and specimens have become increasingly rare on the mineral market.
Red beryl is the only beryl variety that is practically free of alkalis and water of crystallization, because it crystallized at high temperatures (~300-600°C) and under strongly oxidizing conditions in steeply inclined fissures of rhyolitic lava (Shigley et al. 2003).
The unique violet-red color of these beryls is caused by trivalent manganese, in combination with relatively high contents of trivalent iron. In addition, there are significant contents of titanium, which also replaces some of the aluminum in the crystal lattice (Tempesta et al. 2020), corresponding to a real formula close to Be3(Al1.80Fe3+0.10Mn3+0.05Ti0.05) [Si6O18].
Stefan Weiß

Sources: Ream, L. (1979), Mineral. Record 10, pp. 261-278.– Shigley, JE; Thompson, TJ & Keith, JD (2003), Gems & Gemology 39, pp. 302-313.– Tempesta, G.; Bosi, F. & Agrosì, G. (2020), Geostandards and Geoanalytical Research 44, pp. 685-693.